Structural Analysis And Optimization Of Nested-rings MEMS Vibratory Gyroscope

Vibratory gyroscope is a kind of angular rate sensor that is based on the Coriolis coupling of two mechanical modes.Among them,MEMS based vibratory gyroscope shows its superiorities in size,power,and cost.However,the precision of the state-of-the-art MEMS vibratory gyroscope is limited due to the high relative error of MEMS fabrication process and low sensitivity of small size device.This study focuses on the nested-rings disk resonator gyroscope,which is one of the most promising candidates of next generation MEMS gyroscope.We start from gyroscopic dynamics analysis,based on which,some efficient design methods are developed.Moreover,we conceive phonon-cavity electromechanics study in a gyroscopic disk resonator,aiming to expand the method of manipulating MEMS gyroscope.Contributions are summarized as follows.1.On the basis of the Coriolis coupled two-dimensional resonator model,we analyze the open-loop and force-to-rebalance mode dynamics of the vibratory gyroscope,respectively.The explicit mathematical expressions of the gyroscope performances and errors are provided,which provide good guidelines for further structural design and optimization.In addition,the basic theoretical models for frequency trimming and damping tuning are presented.2.The intrinsic and dynamical mode couplings in a nested-rings disk resonator are elaborated upon.Firstly,the mechanical mode coupling between a pair of hybrid states caused by stiffness asymmetry is discussed,based on which,an anti-Stokes sideband induced dynamical coupling is implemented.Moreover,we present an interpretation of the dynamical wave mixing process based on multiple-time-scale perturbation method.Secondly,we observe a nonlinear parametric mode coupling phenomenon,which acts inversely to the well-known tension induced parametric mode coupling.More importantly,we demonstrate that the mode coupling found here is mediated by nonlinear electrostatic field,which has never been cognized before.We demonstrate a three mode dynamical coupling system based on the electrostatic parametric mode coupling and hybrid coupling.3.We construct a dynamic-parameter-calculating platform based on finite element method,which can evaluate overall performance of any input disk resonator.This calculating platform is used as fitness function to study the influences of structural parameters on gyroscope performances.Most importantly,the ring thickness distribution of the nested-rings disk resonator is optimized using single-and multiple-object particle swarm optimization methods.4.The most important factor for the performance of the vibratory gyroscope is the decaying time constant.This study lucubrate the physical mechanism of realizing long in micro-scale mechanical resonator.A novel stiffness-mass decoupling designing strategy to enhance is demonstrated and verified by specially designed nested-rings disk resonators.A stiffness-mass decoupled disk resonator gyroscope prototype operated in the force-to-rebalance mode is developed.A bias stability of 0:08?/h and an angle random walk of 0:012?=ph are experimentally demonstrated in ambient environment.The errors of the prototype are mainly contributed by circuitry,and the potential of our resonator could be much higher.